Extensive research has been directed to the preparation and evaluation of organic phosphite compounds as stabilizers. A number of aromatic phosphorus containing stabilizers for polymers are known. Some of these are effective against heat degradation of polymers and some of them find use in combination with other stabilizers for the same or different functions. While some of these have been made available commercially, many of them have limited application because of deficiencies that limit their general application. Many of these phosphorus containing materials are expensive and they have varying degrees of effectiveness when combined with other stabilizers. Further, some of the most effective materials have some deficiencies such as lack of hydrolytic stability and the like. New phosphite compounds that are effective anti-oxidants, are readily and inexpensively prepared, and that particularly exhibit enhanced polymer protection against heat and oxygen when combined with hydroxyphenyl isocyanurate compounds and other hindered or partly hindered phenol compounds are desired.